Suppression of HIV-1 in CNS by a novel protein from St. John's Wort.+ The transcription process is the first step in the reactivation of HIV-1 genome that eventually leads to complete cytolytic destruction of host cells. As such, since the discovery of HIV-1 there has been a major effort to understand the mechanism by which the viral genome is transcribed and to identify the therapeutic strategies to intervene in this process. In the central nervous system (CNS), microglia, macrophages, and astrocytes are the primary cells that harbor HIV-1 and support, albeit to various degrees, expression and replication of the HIV-1 genome. Earlier studies have ascribed important roles for several transcription factors such as the C/EBPa family, NFkB (p50/p65), and the viral transactivator, Tat, and the late auxiliary protein, Vpr, in these cells. Further, it was evident that cross-interplay of these factors with each other and their specific partners are the key determinants of their activities. Of particular interest was the notion that some of the pathways that are involved in the activation of the HIV-1 genome by Tat also engaged in dysregulated expression of host factors that are implicated in the neuropathogenesis of AIDS. Thus, targeting of these specific viral and cellular activators may provide an effective tool for blocking direct and indirect pathways that are involved in AIDS/CNS injury. In this research proposal we build on our preliminary data indicating that a novel protein, p27SJ, derived from a callus culture of Hypericum perforatum (also known as St. John's Wort) has the ability to physically and functionally interact with Tat and C/EBPa, and impairs their activities upon the HIV-1 genome in microglia and astrocytes. We propose to launch a comprehensive study to 1) unravel the molecular basis of p27SJ suppression of HIV-1 by assessing the interplay of C/EBPa and Tat, and their impact on the overall contribution of various transcription factors that are implicated in LTR transcription. The outcome of this molecularly based project will provide important information and biological tools which, in turn, can be utilized in the future to devise therapeutic tools for halting viral gene expression and replication, and blocking Tat-induced stimulation of pro-inflammatory factors which are implicated in the pathogenesis of AIDS associated neurological problems